JPWO2020166517A1 - Polymer compositions, gels, films and particles - Google Patents

Abstract

Provided are polymer compositions having excellent curability and safety, and gels, films and particles having high mechanical strength and applicable to a wide range of applications. A polymer composition containing a water-soluble polymer having a crosslinkable group and polymer particles having a glass transition temperature of 40 ° C. or lower. Preferably, the crosslinkable group is a vinyl group, a (meth) acryloyloxy group, a (meth) acryloylamino group, a vinylphenyl group, a norbornenyl group, and a derivative thereof, and more preferably, the introduction of the crosslinkable group. The ratio is 0.01 to 10 mol% with respect to the repeating unit of the water-soluble polymer having a crosslinkable group.

Description

The present invention relates to polymer compositions, gels, films and particles.

The gel is a material composed of a crosslinked hydrophilic polymer, and has conventionally been used as a super absorbent polymer (SAP), contact lens, or drug delivery regardless of whether it contains water or not (dry). It has been used in a wide range of applications such as daily life, medical care, food, and civil engineering, such as base materials, shock absorbing materials, vibration damping / soundproofing materials, and coating materials. However, the conventional gel has a problem that the mechanical strength is low and the range of application is limited. In order to solve this problem, a double network gel in which the network structures of two types of hydrophilic polymers intrude into each other has been proposed (Patent Document 1).

In recent years, the development of a material modeling method called Adaptive Manufacturing represented by a 3D printer has become active, and the demand for materials adapted to these has been increasing. In particular, in order to make a gel compatible with a 3D printer, "stimulation curability" is required, in which the gel is quickly cured in one step by stimulation with active energy rays or the like. Furthermore, in the medical field, a method of curing and treating a stimulating curable gel in the affected area of a patient (Patent Document 2), an organ model used for surgical practice using a 3D printer, and a precision scaffold for regenerative medicine (non-patented). It is expected to be applied to the manufacture of Document 1).

Since the double network gel can produce an unprecedented gel having both strength and flexibility, it can be used as a gel for a 3D printer, for example. However, the double network gel has problems in applicability to a 3D printer, such as the need to swell the polymerized gel with a monomer solution and the lack of curability due to the polymerization of the monomer.

In order to solve the above problems of the double network gel, attempts have been made to improve the stimulus curability by adding crosslinked gel particles to the gel. This produces crosslinked gel fine particles composed of the first hydrophilic polymer among the two types of hydrophilic polymers constituting the double network gel, and the crosslinked gel fine particles and the monomer constituting the second hydrophilic polymer are used. This is a method of mixing and curing (Patent Documents 3 to 5, Non-Patent Documents 2 to 4). With this method, a double network gel can be produced in one step, so that it is considered to be more applicable to a 3D printer. Based on this idea, it has recently been proposed to apply a gel to which crosslinked gel particles are added to a 3D printer (Patent Document 6 and Non-Patent Document 5).

International Publication No. 2003/0933337 Japanese Patent Publication No. 2008-50021 Japanese Unexamined Patent Publication No. 2008-163055 Japanese Unexamined Patent Publication No. 2010-260929 Japanese Unexamined Patent Publication No. 2015-96560 Japanese Unexamined Patent Publication No. 2017-26680 Special Table No. 10-513408 Gazette Special Table 2002-506813 Gazette

Chemical Reviews, 116, (2016) 1496-1539 Macromolecules, 44, (2011) 7775-7781 Macromolecules, 45, (2012) 5218-5228 Macromolecules, 45, (2012) 9445-9451 Journal of Solid Mechanicals and Materials Engineering, 7, (2013) 163-168

By mixing the crosslinked gel fine particles and the monomer in the gels described in Patent Documents 3 to 6 and Non-Patent Documents 2 to 5, it has become possible to produce a double network gel having excellent mechanical strength in one step. , There was still a problem with curability due to the polymerization of the monomer. In addition, acrylamide is often used as a monomer, and since the monomer itself is extremely toxic, there is a problem that it cannot be used for medical purposes.

On the other hand, the water-soluble polymer having a crosslinkable group has lower toxicity than the above-mentioned monomer and is used for various uses including medical use (Patent Documents 7 and 8). However, there is a problem that only a gel having low mechanical strength can be produced only by curing the water-soluble polymer.

The present invention has been made to solve the above problems, and provides a polymer composition having excellent curability and safety, and a gel, film and particles having high mechanical strength and applicable to a wide range of applications. The purpose is.

As a result of diligent studies by the present inventors, by adding specific polymer particles to a water-soluble polymer having a crosslinkable group, a gel having high mechanical strength can be obtained even if double networking does not occur sufficiently. Based on this finding, further studies were carried out to complete the present invention.

That is, the present invention
[1] A polymer composition containing a water-soluble polymer having a crosslinkable group and polymer particles (x) having a glass transition temperature of 40 ° C. or lower;
[2] The polymer composition according to the above [1], wherein the crosslinkable group is an ethylenically unsaturated group;
[3] The ethylenically unsaturated group is at least one selected from a vinyl group, a (meth) acryloyloxy group, a (meth) acryloylamino group, a vinylphenyl group, a norbornenyl group, and derivatives thereof. 2] The polymer composition according to;
[4] The above-mentioned [1] to [3], wherein the introduction rate of the crosslinkable group is 0.01 to 10 mol% with respect to the repeating unit of the water-soluble polymer having the crosslinkable group. Polymer composition;
[5] The polymer composition according to any one of the above [1] to [4], wherein the polymer particles (x) have an average particle size of 0.01 to 10 μm;
[6] The polymer particles (x) are polymer particles containing at least one monomer unit selected from the group consisting of conjugated diene, aromatic vinyl compound and (meth) acrylic acid ester. 1] The polymer composition according to any one of [5];
[7] A gel obtained by cross-linking the polymer composition according to any one of the above [1] to [6];
[8] A film obtained by drying and cross-linking the polymer composition according to any one of the above [1] to [6];
[9] The present invention relates to particles obtained by drying and cross-linking the polymer composition according to any one of the above [1] to [6].

According to the present invention, a polymer composition having excellent curability and safety, and a gel, film and particles having high mechanical strength and applicable to a wide range of applications can be obtained.

Hereinafter, the present invention will be described in detail. In addition, in this specification, "(meth) acrylic" means a generic term of "methacrylic" and "acrylic".

The polymer composition of the present invention contains a water-soluble polymer having a crosslinkable group and polymer particles (x) having a glass transition temperature of 40 ° C. or lower.

Cross-linking in the present invention refers to cross-linking by at least one stimulus selected from active energy rays, heat and mixing. The water-soluble polymer having a crosslinkable group can be cured by stimulating active energy rays or heat, respectively, by adding a photopolymerization initiator or a thermal polymerization initiator. Further, in the case of the redox-based polymerization initiator among the thermal polymerization initiators, it is also possible to cure by stimulating the mixture of the peroxide-based polymerization initiator and the reducing agent.

In the present specification, the active energy ray means a light ray, an electromagnetic wave, a particle beam, or a combination thereof. Examples of the light beam include far ultraviolet rays, ultraviolet rays (UV), near ultraviolet rays, visible rays, infrared rays, and the like, examples of electromagnetic waves include X-rays and γ rays, and examples of particle beams include electron beams (EB) and proton rays (α). Rays), neutron beams, etc. Among these active energy rays, ultraviolet rays and electron beams are preferable, and ultraviolet rays are more preferable, from the viewpoints of curing speed, availability of irradiation device, price, and the like.

<Water-soluble polymer with crosslinkable group>
The water-soluble polymer having a crosslinkable group refers to a water-soluble polymer containing a crosslinkable group at the side chain or the end of the water-soluble polymer as a raw material.

(Water-soluble polymer)
As the water-soluble polymer which is a raw material of the water-soluble polymer having a crosslinkable group, both synthetic polymers and natural polymers can be used.

Examples of synthetic polymers include polyvinyl alcohol (hereinafter abbreviated as PVA), poly (meth) acrylic acid, poly (meth) acrylamide, poly (N, N-dimethyl (meth) acrylamide), and poly (N). , N-diethyl (meth) acrylamide), poly (N-isopropyl (meth) acrylamide), polyvinylpyrrolidone, polyhydroxyethyl (meth) acrylamide, polyhydroxyethyl (meth) acrylate, polyethylene oxide, polypropylene oxide, polyethyleneimine, poly Examples thereof include allylamine and derivatives thereof.

These synthetic polymers may be copolymerized with other monomers as long as the water solubility is not impaired. The content of the other monomers is preferably less than 50 mol%, more preferably less than 30 mol%, based on the total structural units constituting the synthetic polymer.

Among synthetic polymers, poly (meth) acrylamide derivatives such as polyacrylamide, poly (N, N-dimethyl (meth) acrylamide), poly (N, N-diethylacrylamide), poly (N-isopropylacrylamide); and polyvinyl. Synthetic polymers that do not contain functional groups for the introduction of crosslinkable groups such as pyrrolidone, amino groups, hydroxyl groups, and carboxyl groups are those with functional groups for the introduction of crosslinkable groups, such as hydroxyethyl methacrylate and methacryl. It is necessary to introduce a functional group for introducing a crosslinkable group into the side chain by copolymerizing with an acid or the like. The content of the monomer having a functional group for introducing a crosslinkable group is preferably less than 20 mol% and more preferably less than 10 mol% with respect to all the structural units constituting the synthetic polymer.

Water-soluble polysaccharides and water-soluble proteins are available as examples of natural polymers. Examples of water-soluble polysaccharides are water-soluble cellulose derivatives such as alginic acid, propylene glycol alginate, agarose, hydroxyethyl cellulose, and carboxymethyl cellulose; guar gum, carrageenan, agar, chitosan, gellan gum, dextran, starch, hyaluronic acid, pullulan, heparin. And so on. Examples of water-soluble proteins include collagen, gelatin, albumin and the like.

Among the water-soluble polysaccharides exemplified above, for example, alginic acid is cured by adding calcium ions. In addition, agarose, gellan gum, gelatin, etc. are also dissolved in hot water and cured by cooling. Although it is possible to utilize the curing properties of the natural polymer itself in this way, the crosslinkable group is bonded to the natural polymer in consideration of the selection of the stimulus for curing and the degree of freedom of molding and the application to the 3D printer. It is essential to be there.

(Crosslinkable group)
As the crosslinkable group, it is preferable to use an ethylenically unsaturated group capable of forming a crosslink between the water-soluble polymer chains by using an active energy ray, heat, a redox-based polymerization initiator or the like, and a radical polymerizable group is used. Is more preferable. Examples of the radically polymerizable group include a vinyl group, a (meth) acryloyloxy group, a (meth) acryloylamino group, a vinylphenyl group, a cyclohexenyl group, a cyclopentenyl group, a norbornenyl group, a dicyclopentenyl group and the like. Saturated hydrocarbon groups and derivatives thereof are mentioned. These ethylenically unsaturated groups may be present on either the side chain or the terminal of the water-soluble polymer.

Among the radically polymerizable groups, a vinyl group, a (meth) acryloyloxy group, and a (meth) acryloylamino are used from the viewpoint of improving the curability of the polymer composition of the present invention and the mechanical strength of gels and films described later. At least one selected from the group consisting of a group, a vinylphenyl group, a norbornenyl group, and a derivative thereof is preferable. From the viewpoint of reactivity, a functional group having a terminal unsaturated carbon bond is preferable, and a (meth) acryloyloxy group is more preferable.

Such a crosslinkable group can be introduced via a side chain or a terminal functional group of a water-soluble polymer, for example, a hydroxyl group, an amino group, a carboxyl group, a 1,2-diol group, a 1,3-diol group, or the like. A (meth) acryloyloxy group can be introduced into a hydroxyl group or an amino group by, for example, reacting an acrylate anhydride or a glycidyl methacrylate in the presence of a base. That is, a (meth) acryloyloxy group can be introduced to a hydroxyl group by esterification, and a (meth) acryloylamino group can be introduced to an amino group by amidation. For hydroxyl groups and amino groups, for example, an allyl ether group, which is one of vinyl groups, can be introduced by reacting allyl glycidyl ether in the presence of a base. For the amino group, for example, a vinyl ester group, which is one of the vinyl groups, can be introduced by reacting divinyl adipic acid in the presence of a base. For the carboxyl group, for example, a methacryloyloxy group can be introduced by esterification by reacting with glycidyl methacrylate under acidic conditions. Further, for the 1,2-diol group and the 1,3-diol group, for example, acrolein, 5-norbornene-2-carboxyaldehyde, 7-octenal and the like are reacted in the presence of an acid catalyst to form a vinyl group by acetalization. Can be introduced. Similarly, by acetalization, a vinylphenyl group is reacted by reacting 3-vinylbenzaldehyde, 4-vinylbenzaldehyde, etc., and (meth) acryloyl is reacted by reacting with N- (2,2-dimethoxyethyl) (meth) acrylamide, etc. Amino groups can be introduced. The introduction of the crosslinkable group into the water-soluble polymer can be used in addition to the reactions exemplified, and two or more kinds of reactions may be used in combination.

Examples of the water-soluble polymer having a crosslinkable group include PVA having a crosslinkable group; polyacrylamide having a crosslinkable group, poly (N, N-dimethyl (meth) acrylamide), poly (N, N-diethylacrylamide), and poly. A polyacrylamide derivative such as (N-isopropylacrylamide); a polyhydroxyethyl (meth) acrylate having a crosslinkable group; a polyethylene glycol having a crosslinkable group; a water-soluble cellulose derivative having a crosslinkable group is preferable, and the crosslinkable group is (). It is preferably a (meth) acrylic group, a vinyl group and a (meth) acryloylamino group.

However, if a vinyl group is used among the crosslinkable groups, it may be difficult to cure. Therefore, for example, a polythiol having two or more thiol groups in one molecule is added to a water-soluble polymer having a vinyl group to form a thiol. -The enreaction may be used. The polythiol is preferably water-soluble, and examples thereof include terminal thiols of 3,6-dioxa-1,8-octanedithiol, dithiothreitol, polyethylene glycol dithiol, and multi-arm polyethylene glycol. Since the thiol-ene reaction has a one-to-one reaction between a vinyl group and a thiol group, it is necessary to add the above-mentioned polythiol so that the thiol group is equimolar or less with respect to the vinyl group. With this addition amount, the strength of the gel or film, which will be described later, is controlled, so that the addition amount of the polythiol can be arbitrarily controlled.

The introduction rate of the crosslinkable group is preferably 10 mol% or less, more preferably 5 mol% or less, still more preferably 3 mol% or less, based on the repeating unit of the water-soluble polymer having a crosslinkable group. Further, it is preferably 0.01 mol% or more, more preferably 0.1 mol% or more. If the introduction rate of the crosslinkable group becomes too high, the mechanical strength of the gel or film described later is improved, but the material becomes very brittle.

The degree of polymerization, which is the number of repeating units contained in the polymer chain of the water-soluble polymer in the present invention, is not particularly limited, and those having various degrees of polymerization can be used. However, if the degree of polymerization of the water-soluble polymer is too small, the gel or film described later tends to become brittle. Further, if the degree of polymerization of the water-soluble polymer becomes too large, the viscosity of the aqueous solution becomes high, which tends to make processing difficult. Therefore, the degree of polymerization of the water-soluble polymer is preferably 4 or more, more preferably 9 or more, and even more preferably 14 or more. Further, 30,000 or less is preferable, 10,000 or less is more preferable, and 5,000 or less is further preferable.

The degree of polymerization in the present specification can be obtained by measuring the ultimate viscosity [η] and dividing the viscosity average molecular weight calculated from the Mark-Hoink equation by the molecular weight of the repeating unit contained in the polymer chain. For example, the degree of polymerization of PVA exemplified as a water-soluble polymer is measured according to JIS K 6726: 1994. That is, it is obtained by the following formula from the ultimate viscosity [η] measured in water at 30 ° C. after re-sewing and purifying PVA.
Degree of polymerization = ([η] × 10 ³ / 8.29) ^{(1 / 0.62)}

The water-soluble polymer having a crosslinkable group in the present invention may contain an ionic group, and the content thereof is preferably 20 mol% or less with respect to the repeating unit of the water-soluble polymer. If it contains more than 20 mol% of ionic groups, the water absorption capacity becomes high, and the strength and dimensional stability of gels and films described later may decrease. The ionic group is not particularly limited, and for example, a cationic group and an anionic group can be used, an ammonium salt can be used as the cationic group, and a carboxylate or a sulfonate can be used as the anionic group.

<Polymer particles (x)>
The polymer constituting the polymer particles (x) may be a polymer composed of one kind of monomer unit or a copolymer composed of a plurality of kinds of monomer units. Further, it may be a mixture of a plurality of polymers.

Examples of the monomer include conjugated diene such as butadiene and isoprene; aromatic vinyl compounds such as styrene, α-methylstyrene and tert-butylstyrene; (meth) acrylic acid and salts thereof; and methyl (meth) acrylate. , (Meta) ethyl acrylate, (meth) n-propyl acrylate, (meth) n-butyl acrylate, (meth) isopropyl acrylate, dicyclopentanyl (meth) acrylate, trimethyl propantri (meth) acrylate , (Meta) acrylic acid esters such as allyl (meth) acrylate; (meth) acrylamide; (meth) acrylamide derivatives such as N-methyl (meth) acrylamide, N-ethyl (meth) acrylamide; nitriles such as (meth) acrylonitrile Vinyl ethers such as methyl vinyl ether, ethyl vinyl ether, n-butyl vinyl ether, isobutyl vinyl ether; vinyl esters such as vinyl acetate, vinyl n-propionate, vinyl butyrate, vinyl pivalate; unsaturated dicarboxylic acids such as maleic anhydride and itaconic anhydride. Acrylic acid anhydride; monoolefin such as ethene, propene, n-butene, isobutene; ethylene halide such as vinyl bromide, vinylidene bromide, vinyl chloride, vinylidene chloride, vinyl fluoride, vinylidene fluoride; allyl acetate, allyl chloride Allyl compounds such as; unsaturated dicarboxylic acids such as maleic acid, fumaric acid, and itaconic acid and salts thereof; unsaturated dicarboxylic acid esters such as maleic acid ester and itaconic acid ester; vinylsilyl compounds such as trimethoxysilane; cyclopentadiene, norbornadiene. Cyclic diene such as inden, tetrahydroinden and the like; cyclic ether such as ethylene oxide, propylene oxide, oxetane and tetrahydrofuran; cyclic sulfide such as thiirane and thietan; cyclic amine such as azylidine and azetidine; 1,3-dioxolane, 1 , 3,5-Trioxane, cyclic acetal such as spiroorthoester; cyclic iminoether such as 2-oxozarin, iminoether; lactone such as β-propiolactone, δ-valerolactone, ε-caprolactone; ethylene carbonate, propylene carbonate And the like; cyclic siloxane such as hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane; and the like.

Among these, at least one monomer selected from the group consisting of conjugated diene, aromatic vinyl compound and (meth) acrylic acid ester is preferable from the viewpoint of productivity.

The glass transition temperature of the polymer particles (x) is preferably 40 ° C. or lower, preferably 25 ° C. or lower, in order to efficiently relax and / or dissipate external stress on the gel or film described later. It is more preferably 10 ° C. or lower. Further, it is preferably −100 ° C. or higher. In the present specification, the glass transition temperature can be obtained by differential scanning calorimetry.

When polymer particles (x) having a glass transition temperature of 40 ° C. or lower are contained inside a gel or film described later, the polymer particles (x) disperse and sacrifice the stress when an external stress is applied. By deforming the polymer, the stress can be relaxed and / or collapsed, and by dissipating the stress, the growth of minute cracks generated in the gel or film can be stopped. Therefore, it is presumed that the entire gel or the entire film is prevented from collapsing and the mechanical strength is improved.

When hard particles having a glass transition temperature or the like are added in a range exceeding 40 ° C., the elastic modulus of the gel and the breaking strength itself may be improved, but it is difficult to improve the flexibility.

The polymer particles (x) are not particularly limited as long as the glass transition temperature is 40 ° C. or lower, but it is preferable that the polymer particles (x) can be dispersed in water because they are mixed with a water-soluble polymer having a crosslinkable group in an aqueous solvent.

As the polymer particles (x) of the present invention, polymer particles whose surface is hydrophilic with a surfactant or the like and coated polymer particles are preferable from the viewpoint of dispersibility in water. Specific examples of the coated polymer particles include coated polymer particles having a polymer film (y) that covers at least a part of the polymer particles (x) as described later.

(Coated polymer particles)
The polymer particles (x) may be coated polymer particles having a polymer film (y) that covers at least a part of the polymer particles (x). The polymer constituting the polymer film (y) may be a polymer composed of one kind of monomer unit or a copolymer composed of a plurality of kinds of monomer units. Further, it may be a mixture of a plurality of polymers.

Examples of the monomer include those mentioned in the polymer particles (x), and the same applies to preferred ones.

The glass transition temperature of the polymer film (y) is preferably 30 ° C. or higher, more preferably 40 ° C. or higher, from the viewpoint of preventing fusion between particles and dispersion stability in water. , 50 ° C. or higher is more preferable. Further, it is preferably 250 ° C. or lower.

The content of the polymer film (y) in the coated polymer particles is based on the mass of the entire coated polymer particles from the viewpoint of efficiently relaxing and / or dissipating external stress on the gel or film described later. 1% by mass or more is preferable, 3% by mass or more is more preferable, and 5% by mass or more is further preferable. Further, it is preferably 80% by mass or less, more preferably 60% by mass or less, and further preferably 50% by mass or less.

Further, it is preferable that the polymer film (y) covers the entire polymer particles (x).

The average particle size of the polymer particles (x) and the average particle size of the entire coated polymer particles including the polymer film (y) when the polymer particles (x) are coated polymer particles are preferably 0.01. It is 10 μm, more preferably 0.02 to 1 μm, and even more preferably 0.04 to 0.5 μm. When the average particle size is large, the gel itself tends to become cloudy and lose its transparency, and the particles tend to settle, but even if the content is small, the strength of gels and films, which will be described later, is improved. Can be expected. On the other hand, when the average particle size is small, it is necessary to increase the content in order to improve the strength of gels and films described later, but there is a tendency to develop high transparency. The average particle size in the present invention refers to the average dispersed particle size measured by a dynamic light scattering measuring device described later.

(Method for producing polymer particles (x))
The method for producing the polymer particles (x) is not particularly limited, but the polymer particles (x) can be produced by, for example, emulsion polymerization, suspension polymerization, self-emulsification of a resin, mechanical emulsification, or the like.

In the emulsion polymerization according to the method for producing the polymer particles (x), an emulsifier is usually used. Examples of such emulsifiers include anionic surfactants such as sodium alkylallyl sulfosuccinate, polyoxyethylene lauryl ether acetic acid, sodium alkylbenzene sulfonate, sodium lauryl sulfate, higher fatty acid sodium, and rosin-based soap; alkyl polyethylene glycol and nonylphenol ethoxylate. Nonionic surfactants such as; cationic surfactants such as distearyldimethylammonium chloride and benzalconium chloride; amphoteric surfactants such as cocamidopropyl betaine and cocamidopropyl hydroxysultaine can be used. In addition, polymer surfactants such as partially saponified PVA (saponification degree 70 to 90 mol%), mercapto group-modified PVA (saponification degree 70 to 90 mol%), β-naphthalene sulphonic acid formalin condensate salt, and (meth) ethyl acrylate copolymer. It is also possible to use. Here, the polymer surfactant can function in the same manner as the polymer coating film (y) that coats the polymer particles (x) after the completion of emulsion polymerization. These emulsifiers may be used alone or in combination of two or more. The amount of the emulsifier used is preferably 0.01 to 40% by mass, more preferably 0.05 to 20% by mass with respect to water.

In the emulsion polymerization, a radical polymerization initiator is usually used. Examples of such radical polymerization initiators include water-soluble inorganic polymerization initiators, water-soluble azo-based polymerization initiators, oil-soluble azo-based polymerization initiators, and organic peroxides. Further, a redox-based polymerization initiator may be used as the radical polymerization initiator.

Examples of the water-soluble inorganic polymerization initiator include hydrogen peroxide, sodium peroxodisulfate, potassium peroxodisulfate (potassium persulfate) and the like. Examples of the water-soluble azo-based initiator include 2,2'-azobis [2- (2-imidazolin-2-yl) propane] dihydrochloride and 2,2'-azobis [2- (2-imidazolin-2-yl). Propane] disulfate dihydrate, 2,2'-azobis (2-methylpropionamidine) dihydrochloride, 2,2'-azobis [N- (2-carboxyethyl) -2-methylpropionamidine] hydrate, 2 , 2'-azobis [2- (2-imidazolin-2-yl) propane], 2-2'-azobis (1-imino-1-pyrrolidino-2-methylpropane) dihydrochloride, 2,2'-azobis [ 2-Methyl-N- (2-hydroxyethyl) propionamide] and the like.

Examples of the oil-soluble azo-based polymerization initiator include 2,2'-azobis (4-methoxy-2,4-dimethylvaleronitrile), 2,2'-azobis (2,4-dimethylvaleronitrile), and 2,2'. -Azobis (isobutyronitrile), 2,2'-azobis (2-methylbutyronitrile), 1,1'-azobis (cyclohexane-1-carbonitrile), 1-[(1-cyano-1-methyl) Ethyl) azo] formamide, 2,2'-azobis [N- (2-propenyl) -2-methylpropionamide], 2,2'-azobis (N-butyl-2-methylpropionamide), dimethyl 2,2 -Azobis (isobutyrate) and the like can be mentioned.

Examples of the organic peroxide include diacyl peroxides such as bis-3,5,5-trimethylhexanoyl peroxide, dilauroyl peroxide, and dibenzyl peroxide; 1,1,3,3-tetramethylbutylhydroperoxide. , Cumenhydroperoxide, hydroperoxides such as t-butylhydroperoxide; dicumylperoxide, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, 1,3-bis (t). -Dialkyl peroxides such as benzene (butylperoxyisopropyl) benzene, t-butylcumyl peroxide, di-t-butyl peroxide, 2,5-dimethyl-2,5-di (t-butylperoxy) hexin-3; Peroxy such as 2,2-bis (4,4-di-t-butylperoxycyclohexyl) propane, 1,1-di-t-butylperoxycyclohexane, 2,2-di-t-butylperoxybutane, etc. Ketal; 1,1,3,3-tetramethylbutylperoxyneodecanoate, α-cumylperoxyneodecanoate, t-butylperoxyneodecanoate, t-butylperoxyneoheptanoeate, t-butylperoxypivalate, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, t-amylperoxy2-ethylhexanoate, t-butylperoxy2-ethylhexanoate Noate, di-t-butylperoxyhexahydroterephthalate, t-amylperoxy3,5,5-trimethylhexanoate, t-butylperoxy3,5,5-trimethylhexanoate, t-butylper Alkyl peroxy esters such as oxyacetate and t-butyl peroxybenzoate; di-2-ethylhexyl peroxy dicarbonate, diisopropyl peroxy dicarbonate, t-butyl peroxyisopropyl carbonate, t-butyl peroxy 2-ethylhexyl carbonate, Examples thereof include peroxycarbonates such as 1,6-bis (t-butylperoxycarbonyloxy) hexane.

The amount of the radical polymerization initiator used is preferably 0.0001 to 1% by mass, more preferably 0.001 to 0.5% by mass with respect to water.

Further, from the viewpoint of productivity, a redox-based polymerization initiator may be used, and the redox-based polymerization initiator is preferably a combination of the organic peroxide and a transition metal salt. Examples of the transition metal salt used in combination with the organic peroxide include iron (II) sulfate, iron (II) thiosulfate, iron (II) carbonate, iron (II) chloride, iron (II) bromide, and iron iodide. Iron compounds such as (II), iron (II) hydroxide, iron (II) oxide; copper (I) sulfate, copper (I) thiosulfate, copper (I) carbonate, copper (I) chloride, copper bromide (II). Copper compounds such as I), copper iodide (I), copper (I) hydroxide, and copper (I) oxide, or hydrates thereof, can be used. Of these, from the viewpoint of productivity, the combined use of cumene hydroperoxide and an iron compound is preferable, and the combined use of cumene hydroperoxide and iron (II) sulfate hydrate is more preferable.

Further, a reducing agent may be used together with the radical polymerization initiator. Examples of such reducing agents include iron compounds such as iron (II) chloride and iron (II) sulfate; sodium salts such as sodium hydrogensulfate, sodium bisulfite, sodium bisulfite, sodium hydrogensulfite, and sodium hydrogencarbonate; ascorbic acid, longalit, and the like. Examples thereof include organic reducing agents such as sodium bisulfite, triethanolamine, glucose, fructose, glyceraldehyde, lactose, arabinose, and maltose. Of these, it is preferable to use an iron compound and an organic reducing agent in combination. The amount of the reducing agent used is preferably in the range of 0.0001 to 1% by mass, more preferably in the range of 0.001 to 0.5% by mass with respect to water.

In the above-mentioned production method, a metal ion chelating agent may be added to the emulsion polymerization system as needed. Specific examples thereof include metal ion chelating agents such as ethylenediaminetetraacetic acid disodium dihydrogen.

In the above-mentioned production method, an electrolyte may be added to the emulsion polymerization system as a thickening inhibitor, if necessary. Specific examples thereof include electrolytes such as sodium chloride, sodium acetate, sodium sulfate and trisodium phosphate. When the emulsifier and the thickening inhibitor are used in combination in the above-mentioned production method, the amount of the thickening inhibitor used is preferably 20% by mass or less with respect to the emulsifier from the viewpoint of the stability of micelles in the emulsion. It is more preferably mass% or less, and further preferably 5 mass% or less.

The reducing agent, metal ion chelating agent and electrolyte may be added during the polymerization reaction, but it is preferable that the reducing agent, the metal ion chelating agent and the electrolyte are added to water from the beginning of emulsion polymerization.

In the above-mentioned production method, a chain transfer agent may be added to the emulsion polymerization system as needed. Examples of the chain transfer agent include mercaptans such as n-octyl mercaptan, n-dodecyl mercaptan, t-dodecyl mercaptan, hexadecyl mercaptan, and n-octadecyl mercaptan; mercaptoacetic acid, mercaptoacetate 2-ethylhexyl, mercaptoacetate methoxybutyl, β-mercapto. Thiols such as propionic acid, methyl β-mercaptopropionate, 2-ethylhexyl β-mercaptopropionic acid, 3-methoxybutyl β-mercaptopropionic acid, mercaptoethanol, 3-mercapto-1,2-propanediol; α-methyl A hydrocarbon compound having a large chain transfer constant such as a styrene dimer can be used.

When using a water-soluble radical polymerization initiator, it may be added as an aqueous solution, but when using a radical polymerization initiator that is sparingly soluble in water, an emulsion of the radical polymerization initiator is prepared in advance using water and an emulsifier. , This may be added. In this case, the emulsifier used may be the same as or different from that used in the emulsion polymerization. Further, two or more kinds of emulsifiers may be combined.

The polymerization temperature of emulsion polymerization is usually preferably in the range of 0 to 100 ° C, and preferably 50 to 90 ° C from the viewpoint of increasing the polymerization rate.

In the present invention, when the polymer particles (x) are used, the emulsion after emulsion polymerization may be used as it is, or the polymer particles (x) may be used by known methods such as salting out, acidification, freezing, and solvent addition. ) May be recovered and used. Further, the polymer particles (x) thus recovered may be further purified by a known method such as washing, reprecipitation, steam stripping and the like.

In the present invention, from the viewpoint of suppressing deterioration of the polymer particles (x), an antiaging agent may be added to the emulsion after emulsion polymerization or the polymer particles (x) after the recovery treatment or the purification treatment. .. From the viewpoint of suppressing deterioration in the recovery treatment and purification treatment of the polymer particles (x) after the polymerization reaction, the anti-aging agent is added to the emulsion after emulsion polymerization and then the polymer particles (x). ) May be recovered or purified. Further, from the viewpoint of suppressing deterioration of the obtained polymer particles (x) during use, an antiaging agent is applied to the polymer particles (x) after the recovery treatment and the purification treatment of the polymer particles (x). It may be added. However, when the anti-aging agent is added to the emulsion after emulsion polymerization, the added anti-aging agent may be removed by the recovery treatment or the purification treatment of the polymer particles (x), so that the polymer particles ( It is desirable to add it again after the recovery treatment or purification treatment of x).

As the anti-aging agent, a general material can be used. Specifically, hydroquinone, hydroquinone monomethyl ether, 2,5-di-t-butylphenol, 2,6-di (t-butyl) -4-methylphenol, mono (or di, or tri) (α-methylbenzyl). ) Phenolic compounds such as phenol; 2,2'-methylenebis (4-ethyl-6-t-butylphenol), 4,4'-butylidenebis (3-methyl-6-t-butylphenol), 4,4'-thiobis Bisphenol compounds such as (3-methyl-6-t-butylphenol); benzimidazole compounds such as 2-mercaptobenzimidazole, 2-mercaptomethylbenzimidazole; 6-ethoxy-1,2-dihydro-2,2, Amine-ketone compounds such as 4-trimethylquinoline, a reaction product of diphenylamine and acetone, 2,2,4-trimethyl-1,2-dihydroquinoline polymer; N-phenyl-1-naphthylamine, alkylated diphenylamine, octylation. Aromatic secondary amine compounds such as diphenylamine, 4,4'-bis (α, α-dimethylbenzyl) diphenylamine, p- (p-toluenesulfonylamide) diphenylamine, N, N'-diphenyl-p-phenylenediamine; Thiourea compounds such as 1,3-bis (dimethylaminopropyl) -2-thiourea and tributylthiourea can be used.

As a method for producing the polymer particles (x), natural rubber, styrene-butadiene copolymer, polybutadiene, polyisoprene, isobutylene-isoprene copolymer, styrene-isoprene copolymer, styrene-isoprene-butadiene co-weight. Polymers such as coalesced, halogenated isobutylene-isoprene copolymer, ethylene-propylene-butadiene copolymer, acrylonitrile-butadiene copolymer, partially hydrogenated acrylonitrile-butadiene copolymer, and rubber such as polychloroprene are previously prepared. It can also be produced by a method of producing them, emulsifying or suspending them in water, and taking them out by spray drying or the like. When polymer particles having a glass transition temperature of 25 ° C. or lower are produced by the above method, the particles fuse with each other and are difficult to redisperse in water or the like. It is a preferable method to emulsify.

<Polymer composition>
The polymer composition of the present invention can be obtained, for example, by mixing the water-soluble polymer having a crosslinkable group and the polymer particles (x) in a solvent.

The concentration of the water-soluble polymer having a crosslinkable group in the polymer composition of the present invention is preferably 1% by mass or more, more preferably 3% by mass or more, still more preferably 5% by mass or more, based on the polymer composition. Further, 70% by mass or less is preferable, 60% by mass or less is more preferable, and 50% by mass or less is further preferable. If the concentration of the water-soluble polymer having a crosslinkable group is less than 1% by mass, the strength of the gel or film described later is low, and if it exceeds 70% by mass, the viscosity of the polymer composition tends to be high and molding tends to be difficult.

The content of the polymer particles (x) in the polymer composition of the present invention is preferably 1% by mass or more, more preferably 2% by mass or more, and further preferably 3% by mass or more, based on the water-soluble polymer having a crosslinkable group. preferable. Further, 300% by mass or less is preferable, and 200% by mass or less is more preferable. If the content of the polymer particles (x) is 1% by mass or more, the mechanical strength of gels and films described later tends to increase, and if it is 300% by mass or less, the water-soluble polymer having a crosslinkable group is cured. Does not inhibit.

The polymer composition of the present invention may contain a solvent, and water is preferable as the solvent. Further, aprotonic polar solvents such as dimethylformamide, dimethylacetamide, dimethylsulfoxide and N-methylpyrrolidone; monoalcohols such as methanol, ethanol, propanol and isopropanol; polyhydric such as ethylene glycol, diethylene glycol, triethylene glycol and glycerin. A water-soluble solvent such as alcohol may be mixed and used.

<Polymerization initiator>
The polymer composition of the present invention preferably contains a polymerization initiator. Examples of the polymerization initiator include a photopolymerization initiator and a thermal polymerization initiator.

As the thermal polymerization initiator, an azo-based polymerization initiator or a peroxide-based polymerization initiator that is generally used in radical polymerization can be used, but a gas is generated in order to obtain a gel or film having excellent transparency and physical properties. A peroxide-based polymerization initiator that does not use is preferable. Further, a redox-based polymerization initiator combined with a reducing agent may be used. As described above, if it is a redox-based polymerization initiator, it can be crosslinked by stimulation of mixing a peroxide-based polymerization initiator and a reducing agent.

When an aqueous solvent is used in the polymer composition, a peroxide-based polymerization initiator having a high water solubility is preferable. Specific examples thereof include inorganic peroxides such as ammonium persulfate, potassium persulfate, and sodium persulfate. Known reducing agents can be used as the reducing agent to be combined as a redox-based polymerization initiator. Among these, highly water-soluble N, N, N', N'-tetramethylethylenediamine, sodium sulfite, sodium hydrogen sulfite, and hydrosal Phytosodium and the like are preferred examples.

As already mentioned, a peroxide-based polymerization initiator that does not generate a gas is preferably used, but a water-soluble azo-based polymerization initiator is used especially when transparency and physical properties of gels and films are not required. You may. Specifically, for example, 2,2'-azobis [2- (2-imidazolin-2-yl) propane] dihydrochloride (trade name "VA-044", manufactured by Wako Pure Chemical Industries, Ltd.), 2, 2'-azobis [2- (2-imidazolin-2-yl) propane] disulfate dihydrate (trade name "VA-044B", manufactured by Wako Pure Chemical Industries, Ltd.), 2,2'-azobis [2-Methylpropion amidine] dihydrochloride (trade name "V-50", manufactured by Wako Pure Chemical Industries, Ltd.), 2,2'-azobis [N- (2-carboxyethyl) -2-methylpropion amidine ] Tetrahydrate (trade name "VA-057", manufactured by Wako Pure Chemical Industries, Ltd.), 2,2'-azobis [2- (2-imidazolin-2-yl) propane] (trade name "VA-" 061 ", manufactured by Wako Pure Chemical Industries, Ltd.), 2,2'-azobis [2-methyl-N- (2-hydroxyethyl) propionamide] (trade name" VA-086 ", Wako Pure Chemical Industries, Ltd. ), 2,2'-azobis (4-cyanopentanoic acid) (trade name "V-501", manufactured by Wako Pure Chemical Industries, Ltd.) and the like.

As the photopolymerization initiator, any agent that initiates polymerization by light rays such as ultraviolet rays (UV) and visible light can be used without any particular problem, but those exhibiting water solubility are preferable. Specifically, for example, α-ketoglutaric acid, 1- [4- (2-hydroxyethoxy) -phenyl] -2-hydroxy-2-methyl-1-propane-1-one (trade name "Irgacure2959", BASF). , Phenyl (2,4,6-trimethylbenzoyl) phosphinic acid lithium salt (trade name "L0290", manufactured by Tokyo Kasei Kogyo Co., Ltd.), 2,2'-azobis [2-methyl-N- (2-methyl-N-) Hydroxyethyl) propionamide] (trade name "VA-086", manufactured by Wako Pure Chemical Industries, Ltd.), Eodine Y and the like.

When the polymer composition containing the photopolymerization initiator is cured, the polymer composition may contain a light absorber. A light absorber is often required to ensure precision when modeling with a stereolithography 3D printer. The light absorber is not particularly limited as long as it exhibits water solubility, but is limited to "KEMIPRO B111" and "KEMISOR B11S" manufactured by Chemipro Kasei Co., Ltd., "Tinuvin 477-DW", "UVA805" and "Tinuvin 1130" manufactured by BASF. Can be mentioned.

When the polymer composition containing the photopolymerization initiator is cured, the polymer composition may further contain a polymerization inhibitor. Examples of the polymerization inhibitor include hydroquinone and p-methoxyphenol showing water solubility, but other polymerization inhibitors can also be used. The storage stability of the polymer composition can be enhanced by adding a polymerization inhibitor.

<Coexistence monomer>
The polymer composition of the present invention may further contain a coexisting monomer. The coexisting monomers include 2-acrylamide-2-methylpropanesulfonic acid, acrylamide, N, N-dimethylacrylamide, (meth) acrylic acid, crotonic acid, itaconic acid, maleic acid, and fumaric acid, which are water-soluble radically polymerizable monomers. , N-isopropylacrylamide, vinylpyridine, hydroxyethyl (meth) acrylate, styrene sulfonic acid, polyethylene glycol mono (meth) acrylate and the like.

<Crosslinking agent>
The polymer composition of the present invention may contain a cross-linking agent. The cross-linking agent is particularly preferably one showing water solubility, and N, N'-methylenebis (meth) acrylamide, ethylene glycol di (meth) acrylate, N, N'- having two or more radically polymerizable unsaturated groups. Examples thereof include diethylene glycol di (meth) acrylate.

<Inorganic particles>
The polymer composition of the present invention may contain water-insoluble inorganic particles. Examples of water-insoluble inorganic particles include silica such as precipitated silica, gelled silica, vapor phase silica, colloidal silica; ceramics such as alumina, hydroxyapatite, zirconia, zinc oxide and barium titanate; zeolite, talc, montmorillonite and the like. Minerals; gypsum such as calcium sulfate; metal oxides such as calcium oxide and iron oxide; metal carbonates such as calcium carbonate and magnesium carbonate; These inorganic particles may be used alone or in combination of two or more. By adding water-insoluble inorganic particles, it is possible to impart functions such as high mechanical properties and magnetism to gels and films described later. It is also possible to obtain a molded inorganic sintered body by drying a gel containing inorganic particles and further performing sintering or the like.

The content of the inorganic particles in the polymer composition is not particularly limited, but is preferably 99.5% by mass or less, more preferably 99% by mass or less, still more preferably 95% by mass or less. Further, in order to obtain the effect of adding the inorganic particles, the content of the inorganic particles is 0.01% by mass or more, more preferably 0.05% by mass or more, still more preferably 0.1% by mass or more.

The polymer composition may contain additives such as dyes, preservatives and fungicides as long as the effects of the present invention are not impaired. These may be used alone or in combination of two or more.

<Gel>
The gel of the present invention is obtained by cross-linking the polymer composition. Examples of the cross-linking method include a method in which the polymer composition is poured into a predetermined mold or the like and then cross-linked by at least one stimulus selected from active energy rays, heat and mixing. Further, when a material extrusion deposition method or an inkjet method is used as in a 3D printer, the polymer composition can be ejected from a syringe or a printer head and then crosslinked by stimulation to form a desired shape. Further, in the stereolithography method, a polymer composition containing a photopolymerization initiator is placed in a bathtub-shaped container and stereolithographically formed to form a desired shape.

The gel of the present invention can be used as it is, but it may be used after being immersed in a solvent such as water to bring it into an equilibrium swelling state. The effect of removing unreacted raw materials and uncrosslinked polymer components by the dipping operation can also be expected. If it is desired to further remove the unreacted raw material and the uncrosslinked water-soluble polymer component, the solvent may be exchanged and the dipping operation may be repeated. However, since the polymer composition of the present invention uses a water-soluble polymer having a crosslinkable group, it has a feature that even if it is used as it is, it hardly shows the toxicity normally exhibited by a monomer.

<Film, particles>
The films and particles of the present invention are obtained by cross-linking and drying the polymer composition. Examples of the cross-linking and drying method include a method of cross-linking the polymer composition as described above to obtain a gel and then drying to obtain the film and particles of the present invention. Alternatively, the film and particles of the present invention can also be obtained by molding the polymer composition, drying it, and then cross-linking it. Examples of the method of forming the polymer composition and then drying it include a method of forming a film by a solution casting method and a method of forming particles by a spray-drying method and then drying.

The film and particles of the present invention can be immersed in water or the like to absorb water again and swell to form a water-containing gel.

The use of the gel, film and particles of the present invention is limited to sanitary products such as paper diapers and sanitary products, medical devices used outside the body such as contact lenses and wound dressings, shock absorbing materials, vibration damping / soundproofing materials, and the like. For more advanced medical equipment such as surface coating of medical equipment and artificial organs, civil engineering and construction materials such as soil improvement materials that require on-site construction, agricultural materials such as water retention materials, and 3D printers that are molded on demand. Examples include curable raw materials.

Next, the present invention will be described in more detail by way of examples, but the present invention is not limited to these examples.

The components used in the synthetic examples, examples and comparative examples are as follows.
(Monomer)
・ N-butyl acrylate: manufactured by Nippon Catalyst Co., Ltd. ・ Trimethylol propantrimethacrylate: trade name “Light Ester TMP”, manufactured by Kyoeisha Chemical Co., Ltd. ・ Allyl methacrylate: manufactured by Tokyo Chemical Industry Co., Ltd. ・ Dicyclopentanyl Ester: Trade name "Funkril FA-513M", manufactured by Hitachi Chemical Co., Ltd. ・ butadiene: manufactured by JSR Co., Ltd. ・ Stylium: manufactured by Kishida Chemical Co., Ltd. (water-soluble polymer)
-Polyvinyl alcohol: trade name "PVA117", manufactured by Kuraray Co., Ltd.-Polyvinyl alcohol: trade name "PVA105", manufactured by Kuraray Co., Ltd. (crosslinking agent)
・ N, N'-methylenebisacrylamide: manufactured by Tokyo Chemical Industry Co., Ltd. (chain transfer agent)
・ N-dodecyl mercaptan: manufactured by Aldrich Japan Co., Ltd. ・ t-dodecyl mercaptan: manufactured by Tokyo Chemical Industry Co., Ltd. (emulsifier)
-Sodium alkylallyl sulfosuccinate: trade name "eleminol JS-20" manufactured by Sanyo Kasei Kogyo Co., Ltd.-Mercapt group-modified PVA (polymerization degree 500, saponification degree 88 mol%): manufactured by Kuraray Co., Ltd.-Sodium lauryl sulfate: trade name "Emar 2FG", manufactured by Kao Co., Ltd., polyoxyethylene lauryl ether acetic acid: trade name "Kao Akipo RLM-100" manufactured by Kao Co., Ltd. (radical polymerization initiator)
・ Sodium peroxodisulfate: manufactured by Wako Pure Chemical Industries, Ltd. ・ Hydrogen peroxide solution: manufactured by Wako Pure Chemical Industries, Ltd. ・ Kumenhydroperoxide: trade name “Park Mill H-80”, manufactured by Nichiyu Co., Ltd. Potassium peroxodisulfate (potassium persulfate): manufactured by Wako Pure Chemical Industries, Ltd. (transition metal salt)
-Iron sulfate (II) (hepatic hydrate): manufactured by Wako Pure Chemical Industries, Ltd. (metal ion chelating agent)
-Ethylenediaminetetraacetic acid disodium dihydrogen: manufactured by Kanto Chemical Co., Inc. (thickening inhibitor)
・ Sodium chloride: manufactured by Wako Pure Chemical Industries, Ltd. ・ Sodium acetate: manufactured by Wako Pure Chemical Industries, Ltd. (anti-aging agent)
-Oligomer type hindered phenol: trade name "Cerozol K-840", manufactured by Chukyo Yushi Co., Ltd. (solvent)
-Ion-exchanged water: Ion-exchanged water with an electrical conductivity of 0.08 x 10 ^-4 S / m or less (hard particles)
・ Colloidal silica: Product name "Snowtex ST-C" (concentration 20% by mass), manufactured by Nissan Chemical Industries, Ltd.

In the synthesis example, various analytical conditions were carried out according to the method shown below.

[Average particle size in emulsion]
Particles of a mixed solution of an emulsion (0.1 mL) of polymer particles (x) and ion-exchanged water (10 mL) using a dynamic light scattering measuring device (device name: FPAR-1000, manufactured by Otsuka Electronics Co., Ltd.). The particle size distribution was measured on a volume basis, and the median diameter was measured as the average dispersed particle diameter, which was used as the average particle diameter in the emulsion.

[Degree of polymerization of water-soluble polymer having crosslinkable group]
The degree of polymerization of the water-soluble polymer having a crosslinkable group obtained in the following synthetic example was measured according to JIS K 6726: 1994.

[Introduction rate of crosslinkable groups]
The introduction rate of the crosslinkable group of the water-soluble polymer having the crosslinkable group obtained in the following synthetic example was measured by proton NMR. The introduction rate is determined from the ratio of the integrated value of the signal of the crosslinkable group and the signal of the water-soluble polymer.
(Proton NMR measurement conditions)
Equipment: Nuclear magnetic resonance equipment "JNM-ECX400" manufactured by JEOL Ltd.
Temperature: 25 ° C
Evaluation in Examples and Comparative Examples was performed according to the method shown below.

[Stimulation hardening]
When the polymer compositions prepared in Examples 1 to 9 and Comparative Examples 1 to 5 below were cured, a gel having a sense of unity was formed as "good", and a gel having a weak but somehow showing a sense of unity was obtained. The formed one was "OK: fair", and the one that could not be treated as a gel because the whole was not cured was "Defective: better".

[Evaluation of gel tensile characteristics]
The tensile characteristics of the gels obtained in Examples 1 to 9 and Comparative Examples 1 to 5 were measured by the following procedure. A test piece was cut out from each gel sheet prepared with a thickness of 2 mm using a JIS K 6251 No. 3 dumbbell cutter. Two gauge points were attached to the test piece using white tape, the distance between the gauge points was measured with a caliper, and the width and thickness of the test piece were measured with a micrometer. Then, the test piece was set in an Easton tensile tester, and the tensile stress and fracture strain were measured at a speed of 100 mm / min while acquiring image data. The initial elastic modulus was simply obtained from the respective stresses corresponding to the strains of 1% and 100%.

[Evaluation of tensile properties of film]
The tensile characteristics of the films obtained in Examples 10 and 11 and Comparative Examples 6 and 7 were measured by the following procedure. After equilibrating the film at a temperature of 23 ° C. and a relative humidity of 45% for 14 days, a test piece was cut out from the produced film using a JIS K 6251 No. 1 dumbbell cutter. Two gauge points were attached to the test piece using white tape, the distance between the gauge points was measured with a caliper, and the width and thickness of the test piece were measured with a micrometer. After that, the test piece was set in an Easton tensile tester, and the fracture strain was measured while acquiring image data. The initial elastic modulus was obtained from each stress corresponding to the strain of 0.05 to 0.25%.

[Synthesis Example 1]
(N-butyl (BA) acrylate / dicyclopentanyl methacrylate (TCDMA) particles)
(Step 1)
After adding 240 g of ion-exchanged water, 91.368 g of "Eleminor JS-20" and 1.08 g of sodium peroxodisulfate to a dried 2 L pressure-resistant polymerization tank, deoxidization treatment is performed by bubbling with nitrogen gas for 30 minutes. And an aqueous solution was obtained. After raising the temperature of the aqueous solution to 60 ° C., a monomer mixture (n-butyl acrylate: trimethylolpropane trimethacrylate: allyl methacrylate = 360: 1.8: 3.6) forming polymer particles (x). Mass ratio)) 365.4 g was deoxidized and then continuously added at a rate of 10 mL / min.

(Step 2)
When it was confirmed that the total monomer conversion rate exceeded 99% by mass, 45 g of dicyclopentanyl methacrylate forming the polymer film (y) was deoxidized in the emulsion obtained in step 1. After that, it was added continuously at a rate of 10 mL / min.

(Step 3)
When it was confirmed that the total monomer conversion rate exceeded 99% by mass, the emulsion obtained in the above step 2 was heated to 100 ° C. and stirred for 2 hours to decompose the residual polymerization initiator. Was done. The polymerization tank was cooled to 25 ° C., and the emulsified solution of the coated polymer particles (BA / TCDMA particles) was taken out. The average particle size in the emulsion was 47.4 nm, and the solid content concentration was 28% by mass. The glass transition temperature of the polymer particles (x) was −55 ° C., and the glass transition temperature of the polymer film (y) was 175 ° C.

[Synthesis Example 2]
(BA / mercapto group-modified PVA particles)
(Step 1)
To a dried 2 L glass polymerization tank, 537.12 g of a 2% by mass aqueous solution of mercapto group-modified PVA, 0.0059 g of iron (II) sulfate (heptahydrate), and 0.145 g of sodium acetate were added to 1N. After adjusting the pH to 5.0 with an aqueous sulfuric acid solution, deoxidation treatment was performed by bubbling with nitrogen gas for 30 minutes to obtain an aqueous solution. After raising the temperature of the aqueous solution to 70 ° C., a mixture consisting of 133.16 g of n-butyl acrylate and 0.66 g of n-dodecyl mercaptan was deoxidized and then added all at once. After that, 86.74 g of a 0.9 mass% hydrogen peroxide aqueous solution was continuously added at a rate of 2.48 mL / min, and polymerization was carried out over 40 minutes with stirring until the addition was completed.

(Step 2)
To the emulsion obtained in the above step 1, 107.42 g of a 10% by mass aqueous solution of mercapto group-modified PVA adjusted to pH 5.0 with a 1N sulfuric acid aqueous solution was deoxidized and then added all at once. Subsequently, a mixture consisting of 133.16 g of n-butyl acrylate and 0.66 g of n-dodecyl mercaptan was deoxidized and then added all at once. After that, 86.74 g of a 0.9 mass% hydrogen peroxide aqueous solution was continuously added at a rate of 2.48 mL / min, and polymerization was carried out over 40 minutes with stirring until the addition was completed.

(Step 3)
The same operation as in Step 2 was performed on the emulsion obtained in Step 2.

(Step 4)
The emulsion obtained in step 3 was subjected to the same operation as in step 3, and then stirred for 4 hours. When it was confirmed that the total monomer conversion rate exceeded 99.5%, the polymerization tank was used. Was cooled to 25 ° C., and an emulsified solution of polymer particles (BA / mercapto group-modified PVA particles) was taken out. The average particle size in the emulsion was 306.3 nm, and the solid content concentration was 33% by mass. The glass transition temperature of the polymer particles (x) was −55 ° C.

[Synthesis Example 3]
(Butadiene / styrene particles)
An emulsion consisting of 3.45 g of cumene hydroperoxide, 3.75 g of sodium lauryl sulfate, and 150 g of ion-exchanged water was deoxidized to obtain an emulsion of a radical polymerization initiator. 200 g of ion-exchanged water, 5 g of sodium lauryl sulfate, 0.032 g of iron (II) sulfate (7hydrate), 0.02 g of disodium dihydrogen tetraacetate of ethylenediamine, 0 g of sodium chloride in a dried 0.5 L pressure-resistant polymerization tank. After adding 2 g, deoxidation treatment was performed by bubbling with nitrogen gas for 30 minutes to obtain an aqueous solution. After raising the temperature of the aqueous solution to 60 ° C., 78 g of butadiene forming deoxidized polymer particles (x) was added. Next, the polymerization was started by continuously adding the radical polymerization initiator emulsion at a rate of 0.02 mL / min. When it was confirmed that the monomer conversion rate exceeded 95% by mass, the obtained emulsion was deoxidized while feeding the emulsion of the radical polymerization initiator at a rate of 0.02 mL / min. 22 g of a monomer mixture (butadiene: styrene: trimethylolpropane trimethacrylate = 2.8: 19: 0.2 (mass ratio)) forming a coalesced film (y) continuously at a rate of 1.7 mL / min. Added. After adding the monomer mixture, when it was confirmed that the monomer conversion rate exceeded 95% by mass, the addition of the radical polymerization initiator emulsion was stopped, and the deoxidized aqueous solution of hydroquinone, which is a polymerization terminator, was stopped. Was added. The polymerization tank was cooled to 25 ° C., and the emulsion of the coated polymer particles (butadiene / styrene particles) was taken out.

The polymerization time from the start of polymerization to the addition of the polymerization terminator was 10 hours. 0.5 g of "Cerozol K-840" was added to the emulsion as an antiaging agent, the average particle size in the emulsion was 48 nm, and the solid content concentration was 34% by mass. The glass transition temperature of the polymer particles (x) was −76 ° C., and the glass transition temperature of the polymer film (y) was 62 ° C.

[Synthesis Example 4]
(BA particles)
3.73 g of "Kao Akipo RLM-100" and 41.7 g of ion-exchanged water were placed in a container, 0.44 g of sodium carbonate was charged while stirring, and the mixture was sufficiently stirred at room temperature to obtain a dispersant. After putting the dispersant in a reaction vessel equipped with a reflux tube, 255 g of ion-exchanged water was added, and the contents were bubbling with nitrogen gas for 30 minutes at room temperature to perform deoxidation treatment, and then the temperature was raised to 70 ° C. It was warm. Then, 0.1 g of potassium persulfate (potassium persulfate) (polymerization initiator) was previously dissolved in 30 g of ion-exchanged water in another container, and deoxidized treatment was performed by the same method as described above. 3.01 g of an aqueous solution of potassium sulfate) was added.

Then, a solution (deoxidized) in which n-butyl acrylate and t-dodecyl mercaptan were mixed was continuously added over 85 minutes using a feed pump. After the addition was completed, the mixture was held for 1 hour, further heated to 90 ° C. and heated for 2 hours. The polymerization tank was cooled to 25 ° C., and the emulsion of the polymer particles (BA particles) was taken out. The average particle size in the emulsion was 93 nm, and the solid content concentration was 31% by mass. The glass transition temperature of the polymer particles (x) was −55 ° C.

[Synthesis Example 5]
[Synthesis of water-soluble polymer with crosslinkable group 1]
40 g (monomer repeating unit: 911 mmol) of "PVA117" was placed in a separable flask equipped with a 1 L Dimroth condenser, 350 mL of DMSO was added, and stirring was started with a mechanical stirrer. The temperature was raised to 80 ° C. by a water bath, and stirring was continued for 4 hours. After visually confirming that PVA had dissolved, 1.2 g (10.8 mmol) of vinyl methacrylate was directly added while heating and stirring, and the mixture was further stirred at 80 ° C. for 3 hours. After allowing to cool, the reaction solution was poured into 2 L of methanol with stirring. Stirring was stopped and the mixture was left as it was for 1 hour. After recovering the obtained solid, it was further immersed in 1 L of methanol for 1 hour for washing. This cleaning work was performed a total of three times. The recovered solid was vacuum dried overnight at room temperature to obtain methacryloyloxylated PVA. The methylenedioxy group introduction rate was 1.2 mol% with respect to the monomer repeating unit of PVA (hereinafter, abbreviated as MA-PVA117 (1.2)).

[Synthesis Examples 6 to 8]
[Synthesis of water-soluble polymers with crosslinkable groups 2-4]
Using the same method as in Synthesis Example 5, methacryloyloxylated PVA having various changes in the degree of polymerization of PVA and the introduction rate of methacryloyloxy groups was produced (Table 1).

[Synthesis Example 9]
[Synthesis of water-soluble polymer with crosslinkable group 5]
60 g (monomer repeating unit: 1.36 mol) of "PVA117" was placed in a separable flask equipped with a 1 L Dimroth condenser, 540 mL of ion-exchanged water was added, and stirring was started with a mechanical stirrer. The temperature was raised to 80 ° C. by a water bath, and stirring was continued for 4 hours. It was visually confirmed that PVA had melted, and the temperature was lowered to 40 ° C. While stirring at 40 ° C., 2.5 g (20.5 mmol) of 5-norbornene-2-carboxyaldehyde and 22 mL of a 10 vol% sulfuric acid aqueous solution were directly added, and the mixture was further stirred at 40 ° C. for 4 hours. After allowing to cool, 80 mL of a 1N NaOH aqueous solution was added to neutralize the mixture, and the mixture was placed in a dialysis membrane having a molecular weight cut off of 3500 and desalted (performed 4 times for 5 L of ion-exchanged water). The desalted aqueous solution was poured into 2 L of methanol with stirring, and the mixture was left as it was for 1 hour. After recovering the obtained solid, it was further immersed in 1 L of methanol for 1 hour for washing. The recovered solid was vacuum dried overnight at room temperature to obtain norborneneized PVA. The norbornene introduction rate was 1.3 mol% with respect to the monomer repeating unit of PVA (hereinafter, abbreviated as Nor-PVA117 (1.3)).

[Example 1]
80 mL of ion-exchanged water was added to 20 g of MA-PVA117 (1.2) and dissolved at 80 ° C. for 4 hours with stirring to obtain a MA-PVA solution. To 15 g of the MA-PVA solution, 4.5 g of an emulsion of BA / TCDMA particles of Synthesis Example 1 (solid content concentration 28% by mass) and 10.5 g of ion-exchanged water were added and stirred. Subsequently, the water-soluble photopolymerization initiator "Irgacure2959" was added in an amount of 0.1% by mass to prepare a polymer composition.

Next, the polymer composition was poured between the glass plates sandwiching a 2 mm thick spacer, and ultraviolet rays (UV) of ^{145 mW / cm 2} (irradiation energy amount: 1200 mJ / cm ^{2) were emitted using a metal halide lamp manufactured by GS Yuasa Co., Ltd.} When irradiated, it was sufficiently cured, and a gel with a sense of unity was obtained.

[Examples 2 and 3]
A gel was prepared in the same manner as in Example 1 except that the blending amounts and types of the water-soluble polymer and the polymer particles were changed as shown in Table 2.

[Example 4]
To 15 g of the MA-PVA solution prepared in Example 1, 0.9 g of the emulsion of BA / mercapto group-modified PVA particles of Synthesis Example 2 (solid content concentration 33% by mass) and 14.1 g of ion-exchanged water were added and stirred. .. Subsequently, 30 mg of ammonium persulfate (APS) and 45 μL of N, N, N', N'-tetramethylethylenediamine (TEMED), which are redox-based polymerization initiators, were added and stirred. Then, a redox-based polymerization initiator was added to prepare a polymer composition, and then the polymer composition was rapidly poured between glass plates sandwiching a spacer having a thickness of 2 mm and cured at room temperature for 1 hour to be sufficiently cured. However, a gel with a sense of unity was obtained.

[Examples 5 to 9]
A gel was prepared in the same manner as in Example 1 except that the blending amounts and types of the water-soluble polymer and the polymer particles were changed as shown in Table 2.

[Comparative Example 1]
90 mL of ion-exchanged water was added to 10 g of MA-PVA117 (1.2) and dissolved at 80 ° C. for 4 hours with stirring to obtain a MA-PVA solution. When 0.1% by mass of "Irgacure2959" was added to 15 g of the MA-PVA solution as a photopolymerization initiator and irradiated with UV by the same method as in Example 1, the gel was sufficiently cured to obtain a gel with a sense of unity. rice field.

[Comparative Example 2]
When UV was irradiated in the same manner as in Comparative Example 1 except that MA-PVA117 (0.6) was used instead of MA-PVA117 (1.2), the gel was sufficiently cured to obtain a gel with a sense of unity. Was done.

[Comparative Example 3]
90 mL of ion-exchanged water was added to 10 g of MA-PVA117 (1.2) and dissolved at 80 ° C. for 4 hours with stirring to obtain a MA-PVA solution. When the MA-PVA solution was cured by the same method as in Example 4, it was sufficiently cured, and a gel having a sense of unity was obtained.

[Comparative Example 4]
An interpenetrating gel formed from the first polymer and the second polymer was prepared as follows with reference to Patent Document 6. 1 mol / L 2-acrylamide-2-methylpropanesulfonic acid (AMPS), 0.04 mol / L N, N'-methylenebisacrylamide (MBAA), and 0.001 mol / L α- as a photopolymerization initiator. A 100 mL aqueous solution containing ketoglutaric acid was irradiated with UV for 7 hours for polymerization to obtain a polyAMPS gel (PAMPS gel) having a degree of cross-linking of 4 mol%. The obtained PAMPS gel was placed in a heat dryer for one day to dry, and then placed in a mortar and crushed to obtain particles of PAMPS gel (hereinafter, may be referred to as a first polymer).

On the other hand, with respect to 1 mol / L of N, N-dimethylacrylamide (DAAm), MBAA of 0.01 mol% with respect to DAAm as a cross-linking agent and 0.1% by mass with respect to a monomer solution as a water-soluble photopolymerization initiator. A monomer solution containing "Irgacure2959" was prepared (hereinafter, may be referred to as a monomer solution forming a second polymer).

The particles of the first polymer are added to the monomer solution forming the second polymer in such an amount that the ratio of the first polymer to the monomer solution forming the second polymer is 1:30 by mass ratio. did. When this solution was irradiated with UV by the same method as in Example 1, the whole was not cured and a gel with a sense of unity could not be obtained.

[Comparative Example 5]
In Comparative Example 5, an interpenetrating gel formed from the first polymer and the second polymer produced in Comparative Example 4 was prepared with a redox-based polymerization initiator. A monomer solution containing 0.01 mol% MBAA with respect to DAAm as a cross-linking agent with respect to 1 mol / L DAAm was prepared. The first polymer prepared in Comparative Example 2 and the monomer solution were mixed in such an amount that the mass ratio was 1:30. When the solution was cured by the same method as in Example 4, a gel that was weak but somehow showed a sense of unity was obtained.

Table 2 shows the formulation of the polymer compositions and the evaluation results of the gels in Examples 1 to 9 and Comparative Examples 1 to 5.

[Example 10]
90 mL of ion-exchanged water was added to 10 g of MA-PVA117 (0.3) and dissolved at 80 ° C. for 4 hours with stirring to obtain a MA-PVA solution. To 50 g of the MA-PVA solution, 1.6 g of an emulsion of BA particles of Synthesis Example 4 (solid content concentration: 31% by mass) and 48.4 g of ion-exchanged water were added and stirred. Subsequently, the water-soluble photopolymerization initiator "Irgacure2959" was added in an amount of 0.1% by mass to prepare a polymer composition.

Next, 60 g of the polymer composition was poured into a tray made of a 20 cm × 20 cm PET film, dried at room temperature, and then 145 mW / cm ² (irradiation energy amount: 1200 mJ / cm) using a metal halide lamp manufactured by GS Yuasa Co., Ltd. ^A film was prepared by irradiating with ultraviolet rays (UV) of 2).

[Example 11]
A film was prepared in the same manner as in Example 10 except that the blending amount of the polymer particles was changed as shown in Table 3.

[Comparative Example 6]
To 50 g of the MA-PVA solution prepared in Example 10, 50 g of ion-exchanged water was added and stirred. Subsequently, the water-soluble photopolymerization initiator "Irgacure2959" was added in an amount of 0.1% by mass to prepare a film in the same manner as in Example 10.

[Comparative Example 7]
To 50 g of the MA-PVA solution prepared in Example 10, 2.5 g of colloidal silica (“Snowtex ST-C” (concentration 20% by mass) manufactured by Nissan Chemical Industries, Ltd.) and 47.5 g of ion-exchanged water were added and stirred. .. Subsequently, the water-soluble photopolymerization initiator "Irgacure2959" was added in an amount of 0.1% by mass to prepare a film in the same manner as in Example 10.

Table 3 shows the formulation of the polymer compositions and the evaluation results of the films in Examples 10 to 11 and Comparative Examples 6 to 7. It can be seen that the film of the present invention showed high breaking strain and the mechanical strength was improved as compared with the film containing no polymer particles.

According to the present invention, gels, films and particles having excellent curability and safety and high mechanical strength can be obtained, so that they can be used outside the body such as sanitary products such as paper diapers and sanitary products, contact lenses and wound dressings. Not limited to medical equipment, shock absorbing materials, vibration damping / soundproofing materials, etc., more advanced medical equipment such as surface coatings of medical equipment and artificial organs, civil engineering / building materials such as soil improvement materials that require on-site construction, It is expected to be applied to various fields such as agricultural materials such as water retention materials and curable raw materials for 3D printers molded on demand.

Claims (9)

A polymer composition comprising a water-soluble polymer having a crosslinkable group and polymer particles (x) having a glass transition temperature of 40 ° C. or lower. The polymer composition according to claim 1, wherein the crosslinkable group is an ethylenically unsaturated group. The second aspect of claim 2, wherein the ethylenically unsaturated group is at least one selected from a vinyl group, a (meth) acryloyloxy group, a (meth) acryloylamino group, a vinylphenyl group, a norbornenyl group, and derivatives thereof. Polymer composition. The polymer composition according to any one of claims 1 to 3, wherein the introduction rate of the crosslinkable group is 0.01 to 10 mol% with respect to the repeating unit of the water-soluble polymer having the crosslinkable group. The polymer composition according to any one of claims 1 to 4, wherein the polymer particles (x) have an average particle size of 0.01 to 10 μm. Claims 1 to 5 where the polymer particles (x) are polymer particles containing at least one monomer unit selected from the group consisting of conjugated diene, aromatic vinyl compound and (meth) acrylic acid ester. The polymer composition according to any one of. A gel obtained by cross-linking the polymer composition according to any one of claims 1 to 6. A film obtained by drying and cross-linking the polymer composition according to any one of claims 1 to 6. Particles obtained by drying and cross-linking the polymer composition according to any one of claims 1 to 6.